The invention has been developed in connection with the operation of a mining-extraction plant for recovering bitumen from the Athabasca tar sands. In such an undertaking, it is necessary to have accurate information as to the composition of the material being mined and processed.
Before the section of the tar sand deposit to be exploited is actually mined, it is usual to drill and recover cores at spaced intervals. Each such cylindrical core of unconsolidated material is recovered from the core barrel in a closed plastic tube. The enclosed core is immediately frozen and stored under sub-zero temperature conditions.
To analyze the cylindrical core, only the inner portion of the core can be used. The mud used during drilling tends to penetrate and therefore contaminate the outer layers of the core.
Heretofore, when the core was to be examined, it would be cut transversely to form two slabs of semi-circular cross-section. One such slab would be examined visually. The other slab would be unfrozen and samples would be spooned out of its central portion at points along its length. These samples would then be analyzed.
A shortcoming of this technique is that the core composition varies along its length and thus the `spot` samples are not as precisely representative as is desirable.